We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagneticallyinduced transparency(EIT)Autler–Townes(AT)splitting spectra obtained using amplitude modulation of the m...We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagneticallyinduced transparency(EIT)Autler–Townes(AT)splitting spectra obtained using amplitude modulation of the microwave(MW)electric field.In addition to the two zero-crossing points interval△f_(zeros),the dispersion signal has two positive maxima with an interval defined as the shoulder interval△f_(sho),which is theoretically expected to be used to measure a much weaker MW electric field.The relationship of the MW field strength E_(MW)and△f_(sho)is experimentally studied at the MW frequencies of 31.6 GHz and 9.2 GHz respectively.The results show that△f_(sho)can be used to characterize the much weaker E_(MW)than that of△f_(zeros)and the traditional EIT–AT splitting interval△f_(m);the minimum E_(MW)measured by△f_(sho)is about 30 times smaller than that by△f_(m).As an example,the minimum E_(MW)at 9.2 GHz that can be characterized by△f_(sho)is 0.056 mV/cm,which is the minimum value characterized by the frequency interval using a vapor cell without adding any auxiliary fields.The proposed method can improve the weak limit and sensitivity of E_(MW)measured by the spectral frequency interval,which is important in the direct measurement of weak E_(MW).展开更多
For enhancing the emission intensity and broadening the excitation region of Ba_3Eu(PO_4)_3(BEP),Sm^(3+) is doped as sensitizer in this paper.BEP:Sm^(3+) can produce an obvious red emission at near ultraviolet(n-UV) r...For enhancing the emission intensity and broadening the excitation region of Ba_3Eu(PO_4)_3(BEP),Sm^(3+) is doped as sensitizer in this paper.BEP:Sm^(3+) can produce an obvious red emission at near ultraviolet(n-UV) radiation.An effective energy transfer from Sm^(3+) to Eu^(3+) is proved.The commission international de I'Eclairage(CIE) chromaticity coordinates of BEP:Sm^(3+) locate at red region.When the environment temperature is 150℃,the emission intensity of BEP:0.10Sm^(3+) is decreased to 76%of the initial one at room temperature,and the activation energy is calculated to be0.164 eV,which can prove the good thermal stability of BEP:Sm^(3+).The results indicate that BEP:Sm^(3+) may have potential applications in white light emitting diodes(LEDs).展开更多
基金Project supported by Beijing Natural Science Foundation(Grant No.1212014)the National Key Research and Development Program of China(Grant Nos.2017YFA0304900 and 2017YFA0402300)+4 种基金the National Natural Science Foundation of China(Grant Nos.11604334,11604177,and U2031125)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB08-3)the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF201807)the Fundamental Research Funds for the Central UniversitiesYouth Innovation Promotion Association CAS。
文摘We have theoretically and experimentally studied the dispersive signal of the Rydberg atomic electromagneticallyinduced transparency(EIT)Autler–Townes(AT)splitting spectra obtained using amplitude modulation of the microwave(MW)electric field.In addition to the two zero-crossing points interval△f_(zeros),the dispersion signal has two positive maxima with an interval defined as the shoulder interval△f_(sho),which is theoretically expected to be used to measure a much weaker MW electric field.The relationship of the MW field strength E_(MW)and△f_(sho)is experimentally studied at the MW frequencies of 31.6 GHz and 9.2 GHz respectively.The results show that△f_(sho)can be used to characterize the much weaker E_(MW)than that of△f_(zeros)and the traditional EIT–AT splitting interval△f_(m);the minimum E_(MW)measured by△f_(sho)is about 30 times smaller than that by△f_(m).As an example,the minimum E_(MW)at 9.2 GHz that can be characterized by△f_(sho)is 0.056 mV/cm,which is the minimum value characterized by the frequency interval using a vapor cell without adding any auxiliary fields.The proposed method can improve the weak limit and sensitivity of E_(MW)measured by the spectral frequency interval,which is important in the direct measurement of weak E_(MW).
基金supported by the National Natural Science Foundation of China(No.50902042)the Natural Science Foundation of Hebei Province in China(Nos.A2014201035 and E2014201037)+1 种基金the Education Office Research Foundation of Hebei Province in China(Nos.ZD2014036 and QN2014085)the College Students Innovation and Entrepreneurship of Hebei University in China(Nos.2014041 and 2015063)
文摘For enhancing the emission intensity and broadening the excitation region of Ba_3Eu(PO_4)_3(BEP),Sm^(3+) is doped as sensitizer in this paper.BEP:Sm^(3+) can produce an obvious red emission at near ultraviolet(n-UV) radiation.An effective energy transfer from Sm^(3+) to Eu^(3+) is proved.The commission international de I'Eclairage(CIE) chromaticity coordinates of BEP:Sm^(3+) locate at red region.When the environment temperature is 150℃,the emission intensity of BEP:0.10Sm^(3+) is decreased to 76%of the initial one at room temperature,and the activation energy is calculated to be0.164 eV,which can prove the good thermal stability of BEP:Sm^(3+).The results indicate that BEP:Sm^(3+) may have potential applications in white light emitting diodes(LEDs).
